In some cases, network access is used for the administration of industrial control systems. In this respect, different public and private networks, such as telephone networks, radio networks, mobile networks, and increasingly the Internet are used. If such access is planned inadequately, configured insecurely, or not monitored, attackers might be able to access individual OT components or the corresponding infrastructure in an unauthorised manner under certain circumstances. This could allow them to bypass the security mechanisms at the perimeter.